I appreciate your concern for the buyer, as I would be also! This is why I stated no "performance loss", I'm not an expert on propeller dynamics or configurations, but to the best of my knowledge engine performance had not diminished between the two propellers.
eg. level flight/cruise speed rpms similar; no issues with climb out; no less or more fuel burn rate than normal
If propeller performance is anything other than what I have stated, then a potential buyer would naturally have the right to return it to me for a refund. However, I'm confident this will not be necessary.
Phil